Conventionally, there is proposed a technique for applying a transmissive screen using a microlens array to a head-up display and a laser projector. When the transmissive screen is used, there is an advantage that it is possible to suppress an influence of a speckle noise compared with a case of using a diffuser. For example, in Patent Reference-1, there is proposed an image forming device including a light source of a laser, a laser projector which projects an image formed by an array of plural pixels, and a microlens array on which plural microlenses are arranged. When the microlens array is used, it is possible to appropriately disperse an incident light and freely design a necessary diffusing angle.
Meanwhile, in Patent References 2 and 3 and Non-Patent Reference 1, there is proposed a screen formed by two microlens arrays or two diffraction gratings, for example. Specifically, Non-Patent Reference 1 discloses that though an uneven brightness tends to occur when only one microlens array is used, the uneven brightness can be suppressed by using two microlens arrays.